1. Field of Invention
The present invention relates to methods to manufacture semiconductor devices and methods to manufacture semiconductor modules, and in particular, is applied to methods to form through electrodes in a substrate.
2. Description of Related Art
In related art semiconductor devices, to realize a stacked layered structure of semiconductor chips, there is a method in which through holes are formed in semiconductor substrates, and the semiconductor substrates are interconnected via through electrodes that are embedded in the through holes.
FIGS. 8(a)-8(d) are cross-sectional views indicating a related art method to manufacture a semiconductor device.
Referring to FIG. 8(a), pad electrodes 52 are formed on a surface 51′ of a semiconductor substrate 51. Opening sections 53 are formed through the pad electrodes 52 in the semiconductor substrate 51. Next, as indicated in FIGS. 8(b) and(c), dielectric films 54 are formed inside the opening sections 53, and embedded electrodes 57 are formed inside the opening sections 53. As indicated in FIG. 8(d), by dry etching a back surface 51″ of the semiconductor substrate 51, the semiconductor substrate 51 is thinned down, thereby making the opening sections 53 penetrate the semiconductor substrate 51. By this, through holes 53′ are formed in the semiconductor substrate 51, the dielectric films 54 are removed, and tips of the embedded electrodes 57 are exposed. As a result, through electrodes 57′ are formed.
However, in the related art method to manufacture semiconductor devices, dry etching is used to expose the tips of the through electrodes 57′. When the dry etching is used in this manner, the etching speed is slow, and therefore the throughput of semiconductor devices is lowered.
However, if wet etching is used to increase the etching speed, variations in the etching amount may occur depending on locations of semiconductor substrates. Consequently, height variations may occur in portions where the through electrodes 57′ protrude from the surface of the semiconductor substrate 51. In this case, when the semiconductor substrate 51 is connected to another semiconductor substrate or a circuit substrate, tip portions of the semiconductor substrate 51 may come in contact with the other semiconductor substrate or the circuit substrate, which causes a problem of lowered reliability.
Therefore, the present invention provides a method to manufacture semiconductor devices and a method to manufacture semiconductor modules, which realize highly reliable semiconductor devices, and are capable of forming through electrodes in good shapes.